Analysis, conjecture; system of ideas.
“Music Theory” is a term that refers to our ideas about the mechanics of music; it can also refer to the study of those ideas.
Theory is an Elemental Card, and points to our ideas regarding what’s at hand. It speaks of intellectual constructs and systems, of analysis and conjecture.
Ideas about a thing, of course, are not the thing; theory can take us only so far. Having coherent ideas about how things work is a necessary step toward mastery; becoming overly identified with our theories, however, can lead us to mistaking the map for the territory. Intoxicating as our ideas may be, they are no substitute for experience and deep understanding.